Device for purging guns



Wyman-a.

May 14, 1957 s. M. sPEAKE ETAL DEVICE FOR PURGING GUNS |.='i1eal.1\p'ri1 28. 194s Smm cer M- EPE-ELKE Wilfred E- Mtlz'ur United States Patent C) l Y 2,191,940' DEVICE non PURGING `GUNS Snmpter M. Speake, Royal Oak, and Wilfred E. Mazur, Detroit, Mich., assignors to the United States of America as represented by the' Secretary of the Army Application April 28,1948, Serial No. 23,742 1s Claims. (el. ssi- 1) (Granted undef Title ss., U; S. carcassa), sec. 266) The invention described in the specification andl claims may be manufactured and used by or for the Government for governmental purposes without-the payment of any royalty thereon.

This invention relates to a device for purging a gun of powder gases or gases of` combustion due to ignition of the combustible or explosive charge when tiring the gun. More particularly, this invention relates to an annulus type scavenging device for automatically purging a gun, together with cartridge cases therein prior tol their ejection from the breech of the gun, when iiring the latter, of a major portion or substantially all of such gases.

ln the operation of a turret mounted gun, for example a 75 mm. gun or larger mounted in the turret or iighting compartment of a combat vehicle, it is importantA that the concentration of after-tiring fumes in the turret or ghting compartment, due to escape therein from the gun breech of such gases, be eliminatedY or reduced as much as' possible to prevent injury to crew members. Heretofore, the concentration of such fumes in the turret or fighting compartment due to such escape has been such a's to be contaminating and toxic, thereby presenting a ventilation problem; and in addition, instances of afterb'urning or flashbacks have occurred' on opening ofthe breech of the gun which have painfully injured crew members. The general problem of ventilation of turct or fighting compartment for the purpose of reducing or eliminating such concentration of after-firing. fumes is greatly simplified if such gases are prevented from entering the turret or compartment by purging the gun and cartridge cases prior to their ejection from the breech of such gases by evacuation of the' latter through the muzzle of the gun'. Purging the gun in this manner Will also eliminate the cause of flashbacks Previously proposed devices for purging guns of such gases by evacuation of the latter through the muzzle lhave required complicated auxiliary equipment, such as compressors Vor storage containers, to provide an external source 'of 'air or Vother purging iiuid under pressure, pipes, or numerous moving parts such as delay actingV valves, often involving intricate timing and valving requirements. Disadvantages of `such purging devices are app'arent, particularly with guns mounted in the turrets of combat vehicles where provision of compressors or pressure storage containers for air or other external purging uid is disadvantageous or even impractical, and where the use of such device involving movingparts subject to wear necessitates undesirable and often diicult periodic maintenance.

` It is accordingly an object of this invention to provide an improved automatic device for purging a gun of gases to prevent or substantially reduce escape of `these gases from the breech of the gun when firing the latter, which device eliminates the above stated disadvantages of previously proposed devices.

It is a further object of this invention to provide an improved automatic selt-contained gun purging device which 2,791,940 Peretti Meyltf 19,57

embodies no moving parts and requires nca-external purging iiuid lfo'i its operation;

Other obects and advantages in providing an improved gun purging device of this invention, including simplicity of construction and installation, and economy, eifectiveness, i'c'iency, and simplicity of operation, will be apparent Vfrom a description thereof a's'it proceeds.

An illustrative embodiment o'f the invention is disclosed By way of example ih the following description, and in the' accompanying drawings in which:

Figure l` is a side elevation of a gun with the-device of this invention.

Figure 2 isl a section' taken on la plane indicated by the line z-z ef Figure 1.

Figure 3 is an enlarged sectional view taken on a plne vindicated by the line 3L3 of Figure 2.

Referring now to the structure generally shown in Figure l, numeral 1 ihdiates a gun, such as a 90 mm. gn, including al barrel or tube 2 and suitable breech and tiring mechanism generally indicated by numeral 3. Numeral 5 designates the forward wall of a turret, such as on a combat vehicle (not Shown); Gun 1 is mounted for vertical pivotal movement on its trunnion members 12 within the turret, so that such vertical pivotal movement may beV accomplished by means of any suitable gun elevating mechanism (not shown) within the turret. A rotor member 14 is carried by gun 1 at opening 16 in turret wall 5 to provide protective closure for the'openi'ng 16 at any desired degree oflevation of gun 1. Gun 1 is desirably 'equipped a't its muzzle end with a suitable miz'- zle brake 7, in' accordance with usual practice with a gin of this typ;

The foregoing description with respect to Figure l thus farvis of general rstrlctufe well known the art. Gun' l is shown equipped withvthe device of this invention 'g-ri- 'erally indicated by numeral 1l), near the muzzle end of the gun but behind in uzzle brake 7, and reference is now made particularly to Figure 3 for the detailed description following. Provided externally eri a portieri 20 if 'gun mbe 2 near the muzzle end of the latter are serew threads '22, .portion 20 extending rearwardly from the muzzle end and being of smaller external Adiameter than the remaining portion of tube 2., portion 2t) terminating rearwardly, at the forward end of the' latter, an yannular shoulder 24. A hollow cylinder member or annul'us 26 ts over and around a part of gun tube v'pc'irtion 20, lthus forming an annular chamber A28. A locking nut 30 on 4threads 22 with' a washer 32 at Aei'rd 34 of annulus 26 holds the latterdt its other endo/6 in tight engagement with shoulder 24. Ends34 and 36 of annulus v26 areprovided with respective radially inner tapered portions 35 and 37 in contact with the external surface of 'gun tub'epor'tion 20, lthese tapered end portions 35 and 37 extending longitudinally o-f the axis of gun tube 2 and thereby providing extended areas of snug-lining contact betweenrespe'ctive end portions 35 and 37 'and gun tube portion 20, to decrease any possibility of gas leakage from chamber 28 between respective ends 34 and 36 and gun tube portion 20. Screw threads 22 accommodate iriteijnallyV threaded rearward end portion of lmuzzle brake 7 at the muzzle end of gun 4tube 2 At the rearward end of muzzle brake 7, 'a locking nut' 38 on threads 22, and washer 39, similar torespe'ctive locking Inut 30 and washer 32, holds muzzle brake 7 in position.

Connecting annular chamber 2`8 w ith bore 11 of gun tube 2 are eight holes v40 `d r ille` d symmetrically arop'ndth'e circumference of portion 20 of gun `tube 2, near shoulder 24 andforward of end portion 37. Holes 4tlj'ai'e inclined fice inwardly at an acute angle of about 30 from the of that they extend muzzleward or toward 'the muzzle of ,gun 1 relative to their ,outer ends at chamber 28. Holes 40 are tapped to receive therein exterorly threaded removable nozzle jet inserts 42 having therein internal nozzle passages 44.

The principle of operation of the device of this invention will now be described After a round has been red and the projectile has moved up the gun bore to a point beyond the holes connecting the annular chamber with vthe bore, powder gases and gases of combustion flow through the nozzle passages or jets in the holes and into the annular chamber, thereby pressurizing the latter. The gases, under pressure, are stored in the chamber until the pressure in the gun bore drops below that in the chamber, after which the gases in the chamber pass back through the jets into the gun bore in the form of converging blasts from the jets. These converging blasts move muzzleward in the gun bore, creating a stack action or suction throughout the length of the gun bore, thus causing the residual gases in the gun bore to be ejected from the gun muzzle in an exhausting action. This exhausting action continues for a considerable period of time after the projectile leaves the gun bore, and if the breech mechanism of the gun is opened during this time, a definite scavenging action takes place.

It is obvious that the dimensions of the device of this invention are subject to variation in a wide range, dependent upon size, type, and characteristics of the particular gun. Thus, by way of example but not limited thereto, with a 90 mm. gun, the annular chamber may have a capacity of 0.1-0.3 cubic feet, While the nozzle passages or jets may vary in number from the eight shown in the example and may have at their narrowest point an internal throat diameter of 1/16-52 inch. It is also obvious that the location ofthe device on the gun near the muzzle end thereof is similarly subject to variation; for example, instead of the cylindrical member or annulus being spaced from a muzzle brake when the latter is employed as shown, the annulus or cylindrical member obviously may abut, be keyed to, or be formed integral with a muzzle brake. l

Although a specic embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as indicated in the following claims.

We claim:

l. A device of the character described comprising, in combination, a gun tube having a muzzle and a bore, a closed hollow member surrounding a portion of said tube and spaced from the latter to provide an outer chamber thereon, said chamber being in uid communication with said bore only, and a plurality of passages being disposed -in a common vertical plane at a point entirely between the end walls of said outer chamber and having outer and inner ends connecting said chamber and said bore to provide said fluid communication, said passages being inclined to the horizontal axis of said bore in a direction f inclination such that said inner ends are toward said muzzle end relative to said outer ends.

2. A device of the character described comprising, in combination, a gun tube having a muzzle end and a bore, a closed hollow cylindrical member surrounding a portion of said tube near said muzzle end thereof and spaced from said tube to provide an outer annular chamber thereon, and a plurality of passages in said tube at a 'point entirely between the end walls of said cylindrical member and connecting said chamber and said bore, whereby said chamber is in uid communication with said bore only, said passages having outer chamber ends and inner relatively muzzleward bore ends such that said passages are inclined at an angle to the longitudinal axis of said bore.

3. A device as set forth in claim 2, wherein said angle to the longitudinal axis of said bore is about 30 degrees.

4 4. In a gun of the type having breech mechanism and a tube Vwith a bore equipped at the muzzle end thereof with a muzzle brake, an improved device for automatically purging said bore of gases when tiring said gun, said device comprising a closed hollow cylindrical member surrounding a portion of said tube adjacent said muzzle brake and spaced from said tube to provide an outer annular chamber thereon, means for rigidly holding said cylindrical member on said tube adjacent said muzzle brake, and a plurality of nozzle passages disposed in a common vertical plane at a point entirely between the end walls of said cylindrical member and connecting said chamber and said bore whereby said chamber is in luid communication with said bore only, said passages being inclined to the longitudinal axis of said bore in a direction inwardly toward said muzzle end from said chamber to said bore.

5. A device of the character described comprising, in combination with a gun tube having a muzzle end and a bore, a closed hollow cylindrical member surrounding a portion of said tube neat` said muzzle end thereof and spaced from said tube to provide an outer annular chamber thereon, a plurality of passages in said tube connect- `ing said chamber and said bore said passages being disposed in a common vertical plane fand at a point entirely between the end walls of said cylindrical member, whereby said chamber is in fluid communication with said bore only, said passages having outer chamber ends and inner relatively muzzleward extending bore ends such that said passages are inclined at an angle to the longitudinal axis of said borre, and a nozzle jet insert carried in each of said passages.

6. A device of the character described comprising, in combination with a gun tube having a muzzle end and a bore, a closed hollow cylindrical member surrounding a Vportion of said tube near said muzzle end thereof and lspaced from said tube to provide an outer annular chamber thereon, said cylindrical member having end portions thereof providing extended areas of snug-fitting contact with said tube, means for securing said cylindrical member to said tube, and a plurality of passages in said tube being disposed in a common vertical plane entirely `between the end walls of said cylindrical member and connecting said chamber with said bore, whereby said chamber is in fluid communication with said bore only, said passages having outer chamber ends and inner rela- 'tively muzzleward extending bore ends such that said passages are inclined inwardly at an acute angle to the longitudinal axis of said bore.

7. A device of the character described comprising, in combination with a gun tube having a muzzle end and fa bore, an external chamber surrounding said tube for `a portion of the length thereof and in iluid communication only with said bore, and a plurality of passages in said tube being disposed in a common vertical plane entirely between the end walls of said external chamber 'and providing said fluid communication, said passages being inclined inwardly from said chamber toward said .muzzle end at an acute angle to the `axis of said bore.

8. In combination with a turret mounted gun having a tube with a muzzle end and a bore, an external charn- .her surrounding said tube for a portion of the length thereof and in fluid communication only with said bore, and a plurality of passages in said tube providing said -iiuid communication, said passages extending inwardly toward said muzzle end from said chamber to said bore and being disposed in a common vertical plane entirely between the end walls of said external chamber.

9. In combination with a turret mounted gun having a .tube with a muzzle end and a bore, a closure member .surrounding a portion of said tube, said member having .a part thereof spaced from said tube to provide an outer annular chamber thereon, and a plurality of passages in `said tube connecting said chamber with said bore said passages being disposed in a common vertical plane en- .tirely between the end walls of said outer annular chamber, whereby said chamber is in fluid communication only with said bore, said passages extending inwardly in a direction toward said muzzle end from said chamber to said bore.

10. A device for aspirating noxious gases from the muzzle end of a gun barrel comprising, means forming a pressure tight chamber fixed to the exterior surface of said barrel and adjacent the muzzle end thereof, there being a plurality of passageways disposed in a common vertical plane entirely between the end walls of said pressure tank chamber and providing communication only between said chamber and the bore of said barrel, said chamber first receiving gases under pressure from the explosion of a cartridge in said barrel by way of said passageways, and then exiting the gases by way of said passageways 'into said bore and toward said muzzle end upon a drop in pressure in said barrel below the gas pressure in said chamber.

1l. A device for aspirating noxious gases from the muzzle end of a gun barrel comprising, means formi-ng a pressure tight chamber fixed to the exterior surface of said barrel and 'adjacent the muzzle end thereof, there being a plurality of passageways formed in the Wall of said barrel and providing communication only between said chamber and the bore of said barrel disposed in a common vertical plane entirely between the end walls of said pressure chamber and, said passageways extending inwardly and forwardly toward said muzzle end.

l2. The device of claim 11, including a jet forming insert received in each one of said passageways.

13. A device for aspirating noxious gases from the muzzle end of a gun barrel comprising, means concentric about the muzzle end of said barrel and secured thereto to form a pressure tight chamber about said barrel, there being a plurality of circumferential equiangularly spaced passageways disposed in a common vertical plane entirely between the end Walls of said pressure tight chamber and extending through the wall of said barrel and 6 providing communication only between said chamber and the bore of said barrel, said passageways being inwardly and forwardly inclined relative to the bore of said barrel.

14. The device in claim 13, including a jet forming insert received in each of said passageways, each of said inserts having 'a restricted central bore parallel to its corresponding passageway.

15. A device of the character described comprising, in combination, a gun tube having a muzzle and a bore, a, closed hollow member surrounding a portion of said tube and spaced from the latter to provide au outer pressure chamber thereon, said chamber being in fluid communication with said bore only, there being a plurality of passages having outer and inner ends connecting said chamber and said bore respectively, to provide said fluid communication, said passages being equiamgularly-spaced `elements of a right cone having its aXis coincidental with the bore axis of the gun and its apex toward the muzzle and being disposed entirely between the end walls of said closed hollow member.

References Cited in the tile of this patent UNITED STATES PATENTS 543,567 Browning July 30, 1895 789,687 Edwards -etal May 9, 1905 1,296,193 Johnston Mar. 4, 1919 1,469,918 DeMaine Oct. 9, 1923 1,487,214 Dezendorf Mar 18, 1924 1,864,374 Romberg et al June 21, 1932 2,503,491 Ianz Apr. 11, 1950 FOREIGN PATENTS 585,851 Germany Oct. 11, 1933 437,027 Great Britain Oct. 23, 1935 531,143 Great Britain Dec. 30, 1940 865,829 France Mar. 17, 1941 

